1. Field of the Invention
The present invention relates to a combination lock having a spring bolt which is retracted by the combination lock and which automatically springs out after release of the combination dial.
2. Description of Prior Art
Of the known type combination locks, these utilize a standard mechanical bolt which is moved to an open position or closed position by the actuation of a bolt displacing mechanism responsive to a manually controllable element located on the outside of a door independent of the combination mechanism. Also, of the combination locks utilizing a combination dial, the combination mechanism remains in an open condition when the door is opened and it is required to scramble the numbers, by spinning the dial, after the door is closed. If a person forgets to scramble the combination, the lock remains unlocked and the door can be opened.
Further, known timing mechanisms usually associated with such combination locks have various disadvantages in that they do not offer any self-locking feature after a set time delay has expired. That is to say, they permit the lock to be opened during the time delay, but after the time delay has expired they do not automatically activate a bolt locking mechanism whereby the bolt will relock automatically and can no longer be retracted from the outside of a door. Also, these type locks of the prior art are very complex and expensive.